The present invention relates to supercritical treatment process for the sterilization or deactivation of microorganisms in liquids, such as liquid foods and beverages.
Many liquids, such as commercial processed foods, including, but not limited to, juices, beverages, soups and stews, contain microorganisms that continue to multiply after processing, thereby reducing the safe shelf life of the foods. It is has been known that exposure of microorganisms to very high pressures (e.g. up to 100 kpsi) will reduce the population of various species of microorganisms during batch processing. Furthermore, the high pressure treatment of liquid foods, while deactivating microorganisms, has essentially no negative effect on the taste and appearance of the liquid.
The prior art generally discloses complicated batch processes and apparatus for the deactivation of microorganisms in a liquid. Unfortunately, batch processes can be expensive and inefficient.
In accordance with the teachings of the present invention, a process and an apparatus for the sterilization of a liquid are provided which substantially eliminate or reduce disadvantages and problems associated with prior art devices and techniques. In particular, the process for sterilizing a liquid (which may be a liquid component alone or a liquid component and a particulate component) includes increasing the pressure on the liquid, and rapidly reducing the pressure on the liquid component while maintaining the liquid within an acceptable temperature range.
To produce this process, there is provided an apparatus that includes a pump for introducing a liquid into a pressurized system. The pump is coupled with a first stage intensifier for increasing the pressure of the liquid. A second stage intensifier is coupled to the first stage intensifier to further increase the pressure on the liquid. Although the two-stage increase is preferred, a single stage could also be used. A pressure receiver is connected to the second stage intensifier, the pressure receiver for maintaining the pressure on the liquid for a predetermined period of time. Finally, a pressure reducer is attached to the pressure receiver wherein the pressure reducer receives the liquid and reduces the pressure on the liquid to atmospheric pressure. In addition, a particulate component treatment apparatus can be provided, which includes a receiver, an intensifier, and a mixer, for mixing the particulate component with the liquid component, if particulate components are provided. The particulate component treatment apparatus can also be used on the liquid components, and thus a mixer may not be needed in such cases.
One important technical advantage of the present invention is the fact that it provides a continuous system for sterilizing a liquid, thereby reducing the strain on the apparatus from the repeated cycling of pressurization in the system, and increasing system efficiency. Another important technical advantage of the present invention is that it can be repaired without interrupting the continuous process for sterilization of liquid within the system.
FIG. 1 is a block flow diagram of the total deactivation process.
FIG. 2 is a block flow diagram of the supercritical pressure liquid treatment process
FIG. 3 is a schematic diagram of the liquid supercritical pressure treatment apparatus.
FIG. 4 is a schematic diagram of the supplemental maintenance control system.
FIG. 5 is a schematic cross sectional view of stainless steel lined high pressure tubing.
FIG. 6 illustrates the intensifier system pressure relief system.
FIG. 7 is a schematic view of the pressure let down station.
FIG. 8 is a is a cross sectional drawing of the design for a controllable high pressure high velocity pressure/flow control valve.
FIG. 9 is a cross-sectional view of orifice pressure/flow control system.
FIG. 10 illustrates the thermodynamics of the pressure let down station.
FIG. 11 is a block flow diagram showing the particulate treatment process.
FIG. 12 is a schematic diagram of the single receiver configuration of the particulate treatment apparatus.
FIG. 13 is a schematic diagram of the multiple receiver configuration of the particulate supercritical pressure treatment apparatus.
FIG. 14 is a cross sectional diagram illustrating the pulp treatment batch receiver.
FIG. 15 is a cross sectional drawing of a Graylock coupling used to connect the lined high pressure process tubing.
FIG. 16 is a cross sectional drawing of a first pressurization end plug for the treatment apparatus.
FIG. 17 is a cross sectional drawing of a second pressurization end plug for the treatment apparatus.